Salinity gradient energy: a new source of renewable energy in Australia

Abstract

Energy production in Australia depends heavily on fossil fuel combustion, which has adverse effects on the environment, including climate change. To reduce its reliance on this perilous source of energy, the Australian government has been giving financial incentives to promote renewable energy. Today, renewable energy accounts for less than 5% of the total energy consumption in the country, but this share is estimated to reach 8% by 2030. Australia also expects 20% of the electricity generation to be provided by renewable sources by 2020, representing a significant increase compared to the current share of only 7%. This predicted growth in renewables is a response to the government targets to reduce carbon dioxide emissions, and to financial incentives for research and development on renewables. In this study, salinity gradient energy is presented as a new renewable energy source for Australia. Salinity gradient energy is released in nature, for example, where rivers meet the oceans. When appropriately harnessed, this energy can be turned into power. This article analyses Pressure Retarded Osmosis, a technology available to harness salinity gradient energy, and discusses possibilities for the exploitation of salinity energy in Australia. This research found that the country has significant potential for osmotic power production. Some favourable factors are: 1) The proximity of the major energy consumption centres to the ocean; 2) The high evaporation rates that could be used to generate more concentrated solutions with higher power production potential; 3) The existence of vast areas of salt beds that could be used to generate brine; 4) The projected desalination plants that could be coupled with osmotic power plants and 5) Government incentives for research on renewable energy.